The present invention relates generally to underwater communication equipment, and more particularly to self-contained ultrasonic directional guidance apparatus for use by divers underwater.
Scuba-equipped divers often have a need to find their way back to an anchored surface craft, to relocate an earlier-discovered submerged object, to keep track of a companion diver, or otherwise to navigate underwater. Poor underwater visibility frequently makes visual navigation impossible, and a diver must then rely on his compass or come to the surface for bearings. As those with experience in this field will appreciate, such direction-finding methods have a number of disadvantages, particularly on deep dives or when above-water visibility is impaired.
In recognition of the problems experienced by divers in navigating underwater, various ultrasonic homing or tracking devices have been described in the prior art. None has experienced any appreciable commercial success, however, and this is attributed to the one or more drawbacks which each includes -- excessive complexity and consequent high cost, bulkiness, low reliability, or operating inconvenience. Accordingly, a general object of the present invention is to provide improved underwater directional guidance apparatus without the drawbacks of prior art apparatus.
A more specific object of the invention is to provide a diver guidance system in the form of compact, portable, self-contained units -- an impulse source or pinger capable of generating omnidirectional ultrasonic signals, and an impluse receiver or hydrophone capable of highly directional reception of signals generated by a pinger.
Another object of the present invention is to provide underwater signaling apparatus having multiple operating modes, -- different power or sensitivity levels, for example -- which can be easily and conveniently set or changed by a diver underwater.
A further object of the invention is to provide a directional hydrophone which indicates the reception of signals from a pinger by displaying related light signals for viewing by a diver.
A still further object of the invention is to provide a compact, inexpensively manufactured watertight housing structure for apparatus of the described type, and, more particularly, a structure having simple, reliable and easily operated switching means for controlling the operating modes of the apparatus.
The novel features characteristic of the present invention are set forth with particularity in the appended claims. However, the apparatus of the invention itself, both as to its construction and method of operation, will best be understood by reference to the following detailed description of a preferred embodiment read in conjunction with accompanying drawings.